1. Field of the Invention
This invention relates to an electrical terminal having a longitudinal spring for preventing contact fretting corrosion.
2. Description of the Prior Art
In some applications, for example in the automobile industry, electrical terminals are subject to vibrations that cause small relative micro-movements between mating contacts, which in turn causes fretting corrosion therebetween thereby increasing the contact resistance. In order to overcome fretting corrosion, receptacle terminals have been provided with longitudinal springs, as shown in European patent application 492479, whereby the spring force is less than the frictional force between mating tab and receptacle connector so as to prevent relative movements therebetween.
One of the problems with this design, however, is that it is difficult to manufacture due to the completely closed outer box shape, in particular for miniature contacts. A further problem with the receptacle of EP 492479, is that the longitudinal spring action functions essentially by bending, in the direction perpendicular to the plane of the sheet metal, of a side wall of the box extending between ends of a transverse slot. This means that there is a certain rotational movement of the end portion of the box from which the contacts extend, thereby causing small micro-rotations of the contact arms. For reduced spring forces in the longitudinal direction, which is necessary for example when the contact forces are reduced for some reason, the rotational movements of the contacts will be increased.
It would therefore be desirable to provide a receptacle terminal with improved anti-fretting characteristics.